A liquid crystal display (LCD) has played a leading role in the field of flat panel display due to advantages such as stable picture, realistic image, low radiation, small volume and low energy consumption. A TFT-LCD (thin film transistor-liquid crystal display) is currently a mainstream liquid crystal display.
A very important parameter of the liquid crystal display is a light transmittance, and an important factor that determines the light transmittance is the aperture ratio. Simply speaking, the aperture ratio is a ratio of an effective region that can transmit light to a total region. A liquid crystal panel comprises an array substrate and a color filter substrate, wherein, the planar schematic view of the array substrate is shown in FIG. 1, a gate line 15′ is provided on the array substrate, and a data line 16′ is provided perpendicular to the gate line 15′, the gate line 15′ and the data line 16′ cross each other to define a pixel region, a thin film transistor and a pixel electrode 12′ are disposed in the pixel region, a gate electrode 2′ of the thin film transistor is connected with the gate line 15′, a source electrode 9′ is connected with the data line 16′, and the drain electrode 8′ is connected with the pixel electrode 12′ through a passivation layer through hole 11′. When light is emitted from a backlight source, not all of the light can pass through the panel, for example, a region where a drive chip, a signal wiring, a thin film transistor, a storage capacitor and etc. are disposed may not be completely transmissive, it is also possible that the light passing through the region is not affected by a liquid crystal layer, thus correct gray level cannot be displayed, so a BM (Black Matrix) is needed to shield such region so as not to disturb the correct brightness of other light-transmitting regions, therefore, exemplarily, a remaining effective light-transmitting region is only a region A in FIG. 1, and a ratio of the effective light-transmitting region to a total region is called the aperture ratio. The light transmittance and the resolution can be improved under a condition that the aperture ratio is enhanced, and meanwhile, the brightness of the backlight source need not be too high, thus, the power consumption and the cost can be lowered.
In prior art, to improve the aperture ratio, various factors affecting the aperture ratio are optimized continuously. However, in prior art, the passivation layer through hole usually is not provided above the gate line region, a capacitance Cgs formed between the gate line and the source electrode, the pixel electrode is 30 fF-100 fF, thus a leaping voltage ΔVp is within a range of 0.5V-1.0V; if the passivation layer through hole is provided above the gate line region, the effective light-transmitting region can be increased to a large extent, and thus, the aperture ratio of the pixel can be increased; however, if the passivation layer through hole is directly provided above the gate line, the capacitance Cgs formed between the gate line and the source electrode, the pixel electrode is 200 fF-500 fF, thus the leaping voltage ΔVp is within a range of 2.5V-7.0V, as the leaping voltage is too large, defects such as a image flicker and an image sticking may be incurred.